---
title: "Joint Precursor"
method: POST
path: "/api/v1/cross-physics/helium-starlink/joint-precursor"
tags: ["Helium-Starlink Coupling"]
---

# Joint Precursor

`POST /api/v1/cross-physics/helium-starlink/joint-precursor`

## Request

- Base URL: `https://www.deepmapai.com`
- URL: `https://www.deepmapai.com/api/v1/cross-physics/helium-starlink/joint-precursor`
- Auth: none declared

Joint earthquake precursor score from two atmospheric layers.

Combines ionospheric electron density perturbations (top-side,
inferred from Starlink orbital drag) with ground-level RF
propagation anomalies (bottom-side, from Helium RSSI residuals)
to produce a two-layer precursor score.

Physics:
    P = 0.35 * Delta_rho  (ionospheric anomaly)
      + 0.40 * Delta_RSSI (ground RF anomaly)
      + 0.25 * |r|        (vertical correlation strength)

Risk levels:
    low        P < 0.3
    moderate   0.3 <= P < 0.5
    elevated   0.5 <= P < 0.7
    high       P >= 0.7

Note: This score is probabilistic and supplementary.  It does
NOT constitute an earthquake prediction.  Always combine with
seismic and geodetic observations.

**Pricing:** Included in subscription tiers (legacy list price: GET /api/v1/billing/pricing).

## Query parameters

- `x_api_key` string, nullable

## Request body

- HSCAnalysisRequest: Request body for Helium-Starlink coupling analysis endpoints.
  - `lat` number, required: Latitude in decimal degrees (WGS84)
  - `lon` number, required: Longitude in decimal degrees (WGS84)
  - `radius_km` number: Analysis radius in kilometres (default 50)
  - `include_training` boolean: If True, trigger model retraining with latest data

## Response `200`

Successful Response

- unknown

## Other responses

- `422`: Validation Error

---

[API](https://skmtc.dev/deepmapai/apis/deepmap-ai.md) · [All operations](https://skmtc.dev/deepmapai/apis/deepmap-ai/llms.txt) · [OpenAPI document](https://skmtc.dev/deepmapai/apis/deepmap-ai/revisions/dab995d977d0?raw)